More and more Islamic jihadists, or holy warriors, are joining the rebellion in Syria to overthrow the regime of Bashar al-Assad, following the advice of radical clerics and other leaders of terrorist networks.

“The afterlife is the only thing that matters to me, and I can only reach it by waging jihad,” Abu Ghureir al-Traboulsi, a rebel fighter in Syria, told USA Today in a recent interview.

“Traboulsi says he crossed into Syria and joined the Abu Walid battalion affiliated with the larger Farouk brigade, a powerful unit in the Free Syrian Army, made up of deserters and others from Assad’s military,” according to USA Today.

Aaron Zelin, a fellow at the Washington Institute for Near East Policy, estimates there are could be up to 3,000 foreign jihadists fighting in Syria, “prodded by sermons and statements on websites from some of the top Muslim radicals and terror groups in the world.”

This is a lingering problem for the US, which has continued supporting the Syrian rebel groups in the hopes that they can serve as a proxy force to topple the Assad regime. The US has been funneling weapons from allies in Saudi Arabia and Qatar.

“Most of the arms shipped at the behest of Saudi Arabia and Qatar to supply Syrian rebel groups fighting the government of Bashar al-Assad are going to hard-line Islamic jihadists,” according to top US officials and Middle East diplomats speaking to the New York Times.

“The evidence is mounting that Syria has become a magnet for Sunni extremists, including those operating under the banner of Al Qaeda,” reported the New York Timesway back in July.

The ties jihadists groups are making while fighting in Syria – ironically aided by the US – are likely to hold for years to come, just as they did in Iraq. And while the US has refrained from directly arming the rebels, the limited support being given is bolstering dangerous elements working to further destabilize Syria.